In this satire of British-American relations, Edward G. Robinson stars as Dan Armstrong, a hard-sell American salesman whose company sends him to England to learn how to tone down his act. There he meets some distant relatives, the aristocrats Sir Peter and Lady Challoner (Arthur Wontner and Annie Esmond). They invite him to their mansion for the weekend, where among the house guests are the penniless aristocrats the Duke and Duchess of Glenavon (Nigel Bruce and Constance Collier ) and their daughter Lady Patricia (Luli Deste), as well as a conniving stockbroker, Henry Graham Manningdale (Ralph Richardson). The Duke and Duchess own only an apparently worthless mine in Rhodesia that supposedly contains a metal called magnelite. Manningdale says that he will develop the mine in exchange for permission to marry Lady Patricia. Armstrong also has designs on Patricia, however, and he engineers a scheme to start a company and sell stock in the mine.